As you can imagine it is a challenging, difficult morning. George is on the scene in Florida where another community is in disbelief shocked by devastating violence. This time at that Florida high school on Valentine's day. This image, one that has become all too familiar. Students evacuating with hands up and suspect in that shooting is in custody. New images this morning showing him being taken to jail. George is outside that school. Good morning to you, George. Good morning, guys. That is the school right behind me, Marjory Stoneman Douglas high school, huge school, ten building, more than 3,000 students and if you ask people why did you move to parkland, they say it is for that school. One of the top in the state. Parkland voted consistently one of the safest communities in ameri America until today. 17 killed. 15 injured and the shooter, Nikolas Cruz, is in custody, the 18th school shooting already this year. It is just mid-february. We'll hear from students inside that school and the heroes who helped save the lives and start with Victor Oquendo. He's covered south Florida for many years. This community hit so hard. Reporter: South Florida has never seen anything like this. Marjory Stoneman Douglas high school will be closed for the rest of the week. Some of these images might be disturbing. Oh, my god. Reporter: At 2 in the afternoon gunshots ring out in this south Florida high school. Terrified students hiding in classrooms during the gunman's rampage. Oh, my god. Oh, my god. Reporter: The shooter reportedly first pulls a fire alarm to get more students out of the classroom maximizing potential victims. The fire alarm got pulled and kids were evacuating. I heard five pops. He was just very focused on what he was doing. And that's it. Reporter: When? I was in the classroom and I was like, oh, my gosh, what's happening. Reporter: S.W.A.T. Teams swarming the school and moving inside. I have the gunshot victim. He's by the entrance on the west side of the school. Does he know where the shooter is? We don't know but we're entering the building. Reporter: Erica Duval filming this as she and classmates were rescued by a S.W.A.T. Team. Yeah, breathe, breathe. Breathe. Everyone on the floor. On the floor. Reporter: Terrified children led but from their hiding places with their hands in the air. Students this this classroom waiting in horror for help to arrive. Police, police. Put your phones away. Reporter: Another S.W.A.T. Team enters this auditorium. Everybody down. Reporter: In this classroom screams of anguish as police lead students to safety. Shh. Come on. Follow me. Let's go. Let's go. Let's go. Oh, my god. Reporter: Outside chaos. Students streaming out of the building, some running, many with their hands on their head, a sea of backpacks abandoned on the ground and emergency rescue rushing to the scene. Scenes of relief as parents comforted children who reached safety. This mother was actually right outside the school when the G gunfire began. What did you hear, what did you see? I heard bang, bang, bang, bang, bang, bang then I texted him and my other son, found out that my other son got out. Found him at Walmart. Brought him home with a few friends and then I had been circling waiting for him to call me. Reporter: At 3:00 P.M. The shooter is still at large, but now a possible description. White male, burgundy shirt wearing a black hat and either long black pants or shorts mixed in with a group of students th were running westbound. Reporter: Just before 4:00 P.M. The 19-year-old suspect Nikolas Cruz captured and taken into custody. We have a shooter in custody after he committed this horrific homicidal detestable act. Reporter: The community now struggling to make sense of the unspeakable. You come to the conclusion this is just absolutely pure evil. This has been a day we've seen the worst in humanity. Tomorrow is going to bring out the best in humanity as we come together to move forward from this unspeakable tragedy. Reporter: I've already seen the community come together. Parents and students consoling each other well into the night and for the families of the victims they'll need that support now more than ever. Thanks very much. We're learning more about the 17 people who lost their lives and

This transcript has been automatically generated and may not be 100% accurate.

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